Check out the area you want on gumtree. You will get lots of hits for Asian girls. Phone them up to confirm they offer HE, they all do even though they are obliged to state of gumtree that they don't offer sexual services, but it's good to double check.
Or you could just walk into any massage shop in chinatown. There are dozens of places and it's all on offer. Don't pay more than £20 for HE unless you want other extras.